Thermal Comfort Strategies

IMPROVING THERMAL
COMFORT IN A
NATURALLY VENTILATED
BUILDING
-Joshua Tree EcoHome-
Samantha Dunne
DESC9015 Building Energy Analysis
Faculty of Architecture, Design, & Planning
University of Sydney
May 21, 2016
("18 Small Green Homes", 2011)

1. BACKGROUND
The aim of this project is to increase the thermal comfort of a naturally ventilated house by 20% in
each of it’s zones. The house selected for this assignment is 2 bedroom, 1 bath Joshua Tree
EcoHome located in Sydney, Australia. This house will be analyzed and redesigned according to the
demands from each of its 3 thermal zones, using DesignBuilder software that is powered by
EnergyPlus.
For the purpose of this project, the zone mean air temperature comfort ranges between 19˚C to
25˚C, without further considerations of other comfort parameters. Additionally, the daytime zones
only need to fall within this comfort range during the hours between 7:00 and 20:00, while night
zones must reside within this range from 20:00 to 7:00.
A successful design will ensure that each of these 3 thermal zones reduces the number of
discomfort hours (i.e. hours that reside outside the defined temperature range) by 20% across the
entire year. In order to adequately determine this reduction, a reference model will be presented
to serve as a benchmark for the improvements. According to the assignment, the reference model
of Joshua Tree EcoHome must meet the below criteria:
• constructed from uninsulated heavy weight construction
• fitted with 30% glazing on all orientations, all to be 6mm clear glass with aluminum frames, U-
value 4.0 W/m2, SHGC 0.82 and VLT 0.88
• Windows are to be 50% open 24/7; open from the bottom; and are not to be modulated
• no heating or cooling systems, i.e. conditioned only by natural ventilation & passive solar design
• internal loads (lighting, equipment and people) and schedules for their operation in each zone;
these values must remain the same between the reference and final models
(Thomas & Candido, 2016)
In order to achieve a 20% reduction of thermally uncomfortable hours in each zone, there are a
few rules which must be respected. They are:
• the overall dimension or orientation of the building cannot be altered
• the internal load assumptions (occupancy, lighting and equipment) and their schedules of
operations cannot be altered
Assuming that the above restrictions are followed, both the building fabric and the control of it
can be altered and managed to produce required performance. Key strategies that will be applied
include passive solar design elements, considerations from Climate Consultant, and other climate
response strategies.
By following the outlined strategies for increasing the thermal comfort of the Joshua Tree
EcoHouse, this report will include a detailed description of the simulation runs, output reports,
and a chronological analysis of the strategies implemented and their direct effects. It will conclude
by summarizing the most effective strategies and a critique of why they were effective or not.
Additionally, both the initial and final models will be included with the HTML and ESO files.
Design Controls
Results

According to Climate Consultant, the prevailing winds in Sydney are Southerly and North-Easterly (Fig.
2). Additionally, the Sun Shading Chart (Fig. 3) illustrates that from December to June, shade is needed
for 554 hours, while sun is needed for 866 hours. From June to December, shade is needed only for
254 hours, while sun is needed for 1439 hours. Overall, passive solar gain is ideal with high angle
summer sun shading desired.
2. INTRODUCTION
Originally designed to be a prefabricated mobile home for cooler climates, for the purposes of this
assignment the Joshua Tree EcoHome will be situated in Sydney, Australia.
Location & Climate
("hangar design group: 'joshua tree'", 2010)
Joshua Tree EcoHome Original Model
("Sydney Basin - climate | NSW Environment & Heritage", 2016)
According to the Building Code
of Australia, Sydney resides
within a warm temperate climate
zone. The climate here is
characterized by warm summers
and cooler winters, with the
mean average annual temperate
ranging from 10˚C to 17˚C (Fig 1).
There is no dry season in Sydney,
however rainfall varies across the
region according to distance
from the coast as well as
altitude. Generally, rainfall is
greater in coastal areas or high
altitudes.
Figure 1
Climate Information
Sydney, Australia
Figure 2
Wind Wheel
Sydney, Australia
Climate Consultant, 2016
Figure 3
Sun Shading Chart
Sydney, Australia
Figure 4
Floor Plan
Joshua Tree EcoHome
Figure 5
Section
Joshua Tree EcoHome
("hangar design group: 'joshua tree'", 2010)

• The terminology “day zone” refers to
the living areas, such as the lounge
and kitchen. “Night zone” refers to
the sleeping areas, i.e. the bedrooms.
• The utility and wet zones were
combined, and will not be accounted
for in this analysis. This is due to the
low annual occupancy rates of these
zones.
• The kitchen and lounge will be
combined into one zone for this
analysis.
• Zoning as indicated by Figure 6.
In modelling the Joshua Tree EcoHome in DesignBuilder, the following assumptions were made:
3. REFERENCE MODEL
In order to achieve the most accurate model, the following inputs were made to customize my
reference model at the site level to properly reflect the Sydney climate.
1. Location: Sydney Airport
2. Latitude: -33.93
3. Longitude: 151.18
4. ASHRAE Climate Zone: 3A
5. Elevation above sea level: 6m
6. Exposure to wind: Normal
7. Site Orientation: 90 ˚
8. Ground temperatures according
to the monthly calculated undisturbed
ground temperatures from the Energy
Plus hourly weather data file (Fig. 7).
9. Precipitation assumption: none
10. Green roof assumption: none
11. Outdoor air and CO2 contaminants
Calculation: Off
12. Simulation weather data:
AUS_SYDNEY_IWEC from the
Design Builder hourly weather data file
13. Region: Australia
14. Insulation Standards: Uninsulated
Site Level Parameters
Zoning Assumptions
Figure 6
Zoning
Reference Model
Design Builder
Figure 7
Ground Temperatures
Reference Model
Design Builder

Block Level Parameters
reference model at the block level to properly reflect the Sydney climate.
Activity
Metabolic: Light office work/standing/walking
Construction
Template: Uninsulated, heavyweight
External wall: 3 layers as seen in Figure 8
Brickwork: 100mm
Concrete Block: 87mm
Gypsum Plastering: 13mm
Internal Partitions: 3 layers, as seen in Figure 9
Brickwork: 115mm
Floor: 3 layers, as seen in Figure 10
Timber Flooring: 30mm
Floor Screed: 70mm
Cast Concrete: 100mm
Roof: pitched, 3 layers as seen in Figure 11
Clay Tile: 25mm
Air Gap: 20mm
Roofing Felt: 5mm
Airtightness: not modelling infiltration
Openings
Glazing template: Single glazing, clear, no shading
Glazing type: Single clear 6mm
SHGC: 0.82
Light Transmission: 0.88
U-Value: 4.0
Glazing layout: 30%
Free aperture opening position: 2-Bottom
Free aperture % glazing area opens: 50%
Lighting
No changes on the block level
HVAC
Mechanical ventilation: off
Domestic hot water: on
Natural ventilation: on
Figure 10
Floor Construction
Reference Model
Design Builder
Figure 11
Roof Construction
Reference Model
Design Builder
Figure 9
Internal Partition Construction
Reference Model
Design Builder
Figure 8
External Wall Construction
Reference Model
Design Builder

Zone Level Parameters
reference model at the zone level to properly reflect the Sydney climate.
ACTIVITY
Zone 1 - Master Bedroom Zone 2 - Bedroom Zone 3 - Living
Template Domestic Bedroom Domestic Bedroom Domestic Lounge
Floor Area (m2) 7.06 4.4 10.89
Occupancy Density
(people/m2)
.283 .227 .2754
Occupancy
Schedule
Assumption: 2 people
Assumption: Night Zone
Modified default template
to reflect that on weekdays
1 occupant will return to
the bedroom at 22:00 and
the other at 23:00. The
weekend and holiday
schedule remained the
same.
Assumption: 1 person
Assumption: Night Zone
Modified default
template to reflect that
on weekdays the 1
occupant will return to
the bedroom at 22:00.
The weekend and
holiday schedule
remained the same.
Assumption: 3 people
Assumption: Day Zone
Modified default template
to reflect that on weekdays
3 occupants will remain in
the zone until 22:00, and 1
until 23:00. Modified the
weekend template to
reflect that 1 person may
be home during the day.
Metabolic activity Bedroom/dwelling Bedroom/dwelling Eating/drinking
Computers Off Off On
Office Equipment
Gain (W/m2)
Off Off 3.5
Office Equipment
Schedule
Assumption: no computers
or office equipment in
bedroom
Assumption: no
computers or office
equipment in bedroom
Assumption: both office
equipment and computers
Default gain W/m2: 3.9
Modified gain:
Television LCD: 3W
Media hub: 8.2W
Computer: 12W
Phone: 2.5W
Modem wireless: 8.6W
Printer: 6.2W
Wireless router: 5.4W
Total watts: 45.9 watts
Final W/m2: 4.1W/m2
To calculate these
numbers, I used YourHome
from the Australian
Government page on
energy.
("Appliances | YourHome", 2016).
Figure 12
Activity Settings and Schedules
Reference Model

Lighting:
The illuminance was set according to the Australian Standard: AS/NZS 1680.2.2 – Interior and Workplace
Lighting ("Interior Lighting Levels", 2013).
Target illuminance Bedrooms: 100lux
Target illuminance Lounge: 150lux
Other Parameters:
No changes were made to the zone level regarding construction, openings, or HVAC.
Comfort Hours of Reference Building
In order to determine the discomfort hours of the Joshua Tree EcoHome reference building, it is first
important to define the total annual hours that each zone will consider for analysis. For the purpose of
this design, it is assumed that the daytime times will be occupied from 7:00 – 20:00, while the night
zones will be occupied from 20:00 - 7:00. Both the day and night zones are assumed to have the same
occupancy hours for 7 days a week, all year long.
Next, the total number of hours in a year must be calculated : 24 hours x 365 days = 8,760 hours
Now that these assumptions have been made, it is possible to begin calculating the current discomfort
hours and the target discomfort hours for each of the three zones.
Zone 1 Master Bedroom – Night Zone
Figure. 13
Daily Operating Hours: 20:00-7:00 = 11 hours
Annual Operating Hours: 11 hours x 365 = 4,015 hours
Annual Comfort Hours: 1,513
Annual Discomfort Hours: 4,015 – 1,513 = 2,502
20% of total discomfort hours: 2,502 x .20 = 500.4
Target Discomfort Hours: 2,502 – 500.4 = 2,001.6
Figure 13
Zone 1 Master Bedroom Discomfort Hours
Reference Model
Energy Plus

Zone 2 Bedroom -- Night Zone
Figure. 14
Annual Comfort Hours: 1,735
Annual Discomfort Hours: 4,015 – 1,735 = 2,280
20% of Total Discomfort Hours: 2,280 x .20 = 456
Target Discomfort Hours: 2,280 – 456 = 1,824
Zone 3 Living Room -- Day Zone
Figure. 15
Annual Comfort Hours: 2,005.5
Annual Discomfort Hours: 4,745 – 2,005.5 = 2,739.5
20% of Total Discomfort Hours: 2,739.5 x .20 = 547.9
Target Discomfort Hours: 2,739.5 – 547.9 = 2,191.6
Figure 14
Zone 2 Bedroom Discomfort Hours
Reference Model
Energy Plus
Figure 15
Zone 3 Living Room Discomfort Hours
Reference Model
Energy Plus

4. CHANGES TO CONSIDER
In order to reduce the annual discomfort hours outlined below, there are various strategies that should
be considered. These strategies include basic climatic design principles as suggested by Climate
Consultant (Figure 16), as well as other design tactics such as scheduling and changing the building fabric.
Annual Discomfort Hours
Zone 1: 2,502 Zone 2: 2,280 Zone 3: 2,739.5
Figure 16
Design Guidelines: Sydney, Australia
The following pages will demonstrate changes made to the reference model in order to decrease the
discomfort hours in each zone by at least 20%. These changes will be made according to the strategies
outlined above, and according to an analysis of the Energy Plus output data. This information will be
organized by demonstrating the change that was made, accompanied by the new calculation of
discomfort hours, and supported by an analysis of why the strategy did or did not produce the expected
results. It is expected that the 20% reduction of discomfort hours in each zone will be achieved in less
than 20 simulation runs Sydney’s mild climate.
5. DESIGN PROCESS

Changes Made
Heavy weight construction to best-practice lightweight construction; changes made to all zones.
BEFORE AFTER
ZONE Discomfort
Hours
BEFORE
Discomfort
Hours
AFTER
Discomfort
Hours
GOAL
Zone 1 2,502 2,494 2,001.6
Zone 2 2,280 2,279 1,824
Zone 3 2,739.5 2,657 2,191.6
The changes improved the over all comfort hours of all
three zones. In particular, both the discomfort hours
below 19˚ and above 25˚ were reduced throughout the
year. This improvement was effective as expected, as the
typical construction in Sydney’s climate is lightweight. The
non-insulated heavyweight construction was trapping too
much heat in the summer, while allowing too much heat
escape in the winter.
Critique:
Changes Made
From On 24/7 window schedule to a customized window schedule based on seasonal temperatures; changes
made to all zones
BEFORE AFTER
Results:
ZONE Discomfort
Hours
BEFORE
Discomfort
Hours
AFTER
Discomfort
Hours GOAL
Zone 1 2,494 2,374.5 2,001.6
Zone 2 2,279 1,870 1,824
Zone 3 2,657 2,571 2,191.6
Critique:
After customizing the window schedules, each of
the three zones experienced a significant reduction
in the discomfort hours. Particularly, Zone 3 saw a
massive improvement of more than 400 hours
additional comfort. This step was critical as it is
essential to minimize heat loss in Sydney in the
winter, and open windows are a huge source of air
leakage.
Results:
The window operation was
fixed so all windows would be
open the entire year. The
schedule is indicated below:
To make the window operation more fitting
for the climate, Climate Consultant was
used to analyze the high and low
temperatures in each season, as well as the
prevailing wind directions from the Wind
Wheel. See Appendix A. From there, the
windows operation was adjusted to indicate
that they will remain open when the
temperatures are in the comfort range, and
close when the temperatures are below
19˚C. The schedule is indicated to the right:
Run 1
Run 2
(DesignBuilder, 2016)

Changes Made
Glazing changed from clear single glazing on all windows to double glazing on all windows, with low-E glazing on
West, South, and East windows.
BEFORE AFTER
All three zones were one again improved thermally, however
at very minimal intervals. By changing the glazing passive
solar hear gain North was allowed, but perhaps it was not as
effective as it could be when combined with shading. Without
shading, unwanted heat gain happens in the summer months
from both active and passive solar heat gain methods.
However, using Low-E glazing on the other facades will block
long wave radiation from passing through year round,
meaning no wanted heat will leave during winter and no
unwanted heat will accumulate in the summer.
Critique:
Changes Made
Shading changed from no shading on windows to 0.5m overhang shading on North facing windows, and louvres
on East facing windows.
BEFORE
No shading on any window.
AFTER
North windows: East Windows:
Results:
Critique:
This change was unsuccessful. Two zones decreased
their overall comfort hours after adding in the
shading. After further analysis, it appears that the
discomfort hours in all zones are heavily weighted
to overcooling, see Appendix B. Therefore, any
strategies that minimize solar hear gain are, at this
point, increasing the discomfort further.
Results:
ZONE Discomfort
Hours
BEFORE
Discomfort
Hours
AFTER
Discomfort
Hours
GOAL
Zone 1 2,374.5 2,374 2,001.6
Zone 2 1,870 1,844 1,824
Zone 3 2,571 2,567 2,191.6
ZONE Discomfort
Hours
BEFORE
Discomfort
Hours
AFTER
Discomfort
Hours GOAL
Zone 1 2,374 2,390 2,001.6
Zone 2 1,844 1,848 1,824
Zone 3 2,567 2,564 2,191.6
All West, East, and South Windows All North facing windows
Run 3
Run 4
(DesignBuilder, 2016) (DesignBuilder, 2016)

Changes Made
Window operation changed from only focusing on seasonal temperatures to customizing operation in based on
the heating demands of each room. See Appendix C.
BEFORE AFTER
By adjusting the window operation by zone, focusing on
closing the windows when the temperatures were cooler,
actually increased the discomfort hours in each of the zones.
This was a surprising result, as the additional discomfort
hours were part of the “too cold” temperature range. This
change was so unexpected, in fact, that it warrants a
reassessment of the window schedules to make sure the
inputs were entered correctly.
Critique:
Changes Made
Correction of the window schedule. Updated to indicate that windows are closed throughout the winter.
BEFORE AFTER
Critique:
This small but critical fix drastically reduced the
discomfort hours in 2 zones, while having a moderate
reduction in Zone 1. Although these parameters were
the intent of Run 2, this showcases the importance of
attention to detail while scheduling. Zones 2 and 3
have now reached their 20% reduction target. The
remaining runs will focus on Zone 1, and further
reduction of Zones 2 and 3.
Results:
ZONE Discomfort
Hours
BEFORE
Discomfort
Hours
AFTER
Discomfort
Hours
GOAL
Zone 1 2,390 2,422 2,001.6
Zone 2 1,848 1,970.5 1,824
Zone 3 2,564 2,619.5 2,191.6
ZONE Discomfort
Hours
BEFORE
Discomfort
Hours
AFTER
Discomfort
Hours GOAL
Zone 1 2,422 2,355 2,001.6
Zone 2 1,970.5 830 1,824
Zone 3 2,619.5 1,888.5 2,191.6
Zone 1
All Zones
Zone 3Zone 2
Zone 1 Zone 3Zone 2 Zone 1 Zone 3Zone 2
Results:
Run 5
Run 6

Changes Made
Changed from a lightweight floor to a heavyweight flooring in Zone 1, and increased the insulation in the ceiling.
Also changed external walls on south and east from lightweight construction to double brick with insulation
Changes Made
Removed sidefins from North and East shading. Removed windows on South walls of Zone 1 and 3. Added a
window and shading on the West size of Zone 3.
BEFORE AFTER
This change was effective in all three Zones. By replacing the
window on South façade in Zone 3 to the East façade, cross
ventilation was maintained but protection from the winter
cold, and more solar heat gain was introduced. Additionally,
in zones 1 and 2, more solar heat gain will improve winter
temperatures with the lack of sidefins, while the overhang
still protects from unwanted summer sun.
Critique:
Critique:
The added thermal mass and insulation improved the
discomfort hours in zone 1, but it increased the
uncomfortably cold hours in Zone 3 drastically.
Although the target discomfort hours for Zone 3 are
still met, it is curious why these changes to Zone 1
would affect Zone 3. It is perhaps due to the heat that
would normally be in the hallway being transferred to
the thermal mass in the adjacent Zone 1, thus reducing
the temperature in Zone 3 – however it is uncertain.
Results:
ZONE Discomfort
Hours
BEFORE
Discomfort
Hours
AFTER
Discomfort
Hours
GOAL
Zone 1 2,355 2,318 2,001.6
Zone 2 830 799.5 1,824
Zone 3 1,888.5 1,868 2,191.6
ZONE Discomfort
Hours
BEFORE
Discomfort
Hours
AFTER
Discomfort
Hours GOAL
Zone 1 2,318 2,291 2,001.6
Zone 2 799.5 800 1,824
Zone 3 1,868 2080 2,191.6
Results:
Ceiling
Floor
Ceiling
External Wall
Floor
External Wall
BEFORE AFTER
Run 7
Run 8
(DesignBuilder, 2016)(DesignBuilder, 2016)

Changes Made
Due to the unexpected results of the previous run, the window schedules for Zone 1 were checked for accuracy.
This proved that the East window in Zone 1 was still following the reference model scheduling of “open 24/7.” This
was updated to the accurate scheduling indicated in Run 6.
BEFORE AFTER RESULTS
By correcting the window schedule of the Eastern window in Zone 1, the discomfort hours were reduced in
Zone 1 and 3, but increased Zone 2. These increased discomfort hours were in relation to overheating. This is
likely due to the reduction of airflow to Zone 2, as this zone has the least amount of external walls, and
therefore was previously cooled slightly from airflow through internal partitions. Ultimately, this change has
now pushed all 3 zones to the target discomfort hours.
CRITIQUE
ZONE Discomfort
Hours
BEFORE
Discomfort
Hours
AFTER
Discomfort
Hours
GOAL
Zone 1 2,291 912 2,001.6
Zone 2 800 852 1,824
Zone 3 2080 2043 2,191.6
Zone 1Zone 1
Run 9
Comfort Hours of Proposed Building
Zone 1 Master Bedroom -- Night Zone
Figure 17
Reference Model Discomfort Hours: 2,502
Proposed Model Discomfort Hours: 4,015 – 3,103 = 912
Calculation: 912 / 2502 x 100 = 36.45
Total Reduction of Discomfort Hours (%): 100 - 36.45 = 63.55%
Figure 17
Zone 1 Master Bedroom Discomfort Hours
Proposed Model
Energy Plus

Zone 2 Bedroom -- Night Zone
Figure 18
Reference Model Discomfort Hours: 2,280
Proposed Model Discomfort Hours: 4,015 – 3163 = 852
Calculation: 852 / 2280 x 100 = 37.37
Total Reduction of Discomfort Hours (%): 100 – 37.37 = 62.63%
Figure 18
Zone 2 Bedroom Discomfort Hours
Proposed Model
Energy Plus
Figure 19
Zone 3 Living Room Discomfort Hours
Proposed Model
Energy Plus
Zone 3 Living Room -- Day Zone
Figure 19
Reference Model Discomfort Hours: 2,739.5
Proposed Model Discomfort Hours: 4,745 – 2,702 = 2,043
Calculation: 2,043 / 2,739.5 x 100 = 74.56
Total Reduction of Discomfort Hours (%): 100 – 74.56 = 25.44%

The process of completing each of the design simulations and seeing the varying degree of effectiveness
of each of the changes has highlighted the significance of certain design elements. In particular, changing
the window scheduling had such a massive impact on the number of discomfort hours, in comparison to
other strategies used. As this element was subject to human error during the testing, in particular not
having all of the windows changed during the same simulation, it is of interest to determine the results
of these window schedules isolated from the other design elements. The below chart (Figure 22) reflects
the results of the reference building in comparison to the proposed model with the only change being
the window scheduling.
ZONE Discomfort Hours
REFERENCE MODEL
Discomfort Hours
PROPOSED DESIGN
Discomfort Hours WINDOW
SCHEDULES ONLY
Zone 1 2,502 912 2368.5
Zone 2 2,280 852 1504.5
Zone 3 2,739.5 2043 2195.5
Independent Simulation of Strongest Design Strategy
Figure 22
Reference Model vs Window Scheduling
The results of running a simulation with the only changes to the reference model being to the window
schedules produces interesting results. Alone, the window scheduling does improve the comfort of each
zone by a few hundred hours, however in combination with the other strategies it increases the comfort
drastically. This demonstrates that the best design comes from a sensible combination of strategies, and
cannot be achieved using only one strategy, no matter how seemingly impactful it is.
After analyzing the remaining discomfort hours in each of the zones, it is clear that the proposed design
of Joshua Tree EcoHome is now experiencing more uncomfortably warm hours than uncomfortably cool
hours (Figure 21). Although the design has now decreased the discomfort hours by significantly more
than the targeted 20% (Figure 20), there are still further strategies that can be implemented in order to
reduce those overheated hours.
6. ADDITIONAL CHANGES TO CONSIDER
Figure 20
Before and After Discomfort Hours
Proposed Design
ZONE Discomfort Hours
REFERENCE
MODEL
Discomfort
Hours
GOAL
Discomfort Hours
PROPOSED DESIGN
% REDUCTION
of Discomfort
Hours
Zone 1 2,502 2,001.6 912 63.55%
Zone 2 2,280 1,824 852 62.63%
Zone 3 2,739.5 2,191.6 2043 25.44%
Figure 21
Classification of Discomfort Hours
Proposed Design
Zone Uncomfortably
Cool Hours
Uncomfortably
Warm Hours
Zone 1 331.5 580.5
Zone 2 132 719.5
Zone 3 426.5 1575.5

In order to bring the reference model of the Joshua Tree EcoHome to the proposed model, various
sustainable design strategies were implemented. First, the basic construction of the model was
changed from uninsulated heavy weight, to lightweight construction, as it is more appropriate for the
Sydney climate. Next, the window schedules were changed to reflect seasonal temperature differences.
Modeling this component was undertaken in three different simulations, as human error was involved
in writing the schedules. However, if the scheduling had been implemented correctly on the first run, it
is likely that initial scheduling change would have been sufficient. Next, the glazing was updated based
on appropriate strategies for each direction, that is clear glazing on the North, Low-E on the East and
West, and no glazing on the South. Then, shading was added to the glazing to reduce heat load in the
summer. The shading was then altered in an additional run, as the first design provided too much
shading, effectively blocking desired heat load in the winter. Finally, insulation was added to the walls,
ceiling, and floor in Zone 1, as the other two zones were already at a comfortable annual temperature.
In conclusion, the synthesis of these climatic design strategies have improved the energy efficiency of
the Joshua Tree EcoHome in each of its three zones by 63.55%, 62.55%, and 25.44% respectfully. This
efficiency could be further increased using the proposed additionally strategies outlined above.
7. CONCLUSION
After confirming that the best results are derived from a combination of strategies, it is necessary to
consider additional strategies that would improve the thermal comfort of the proposed Joshua Tree
EcoHouse. As indicated in Figure 17, these strategies should be elements for cooling design due to the
majority of the uncomfortable hours being caused by overheating. The following will outline some of
the additional strategies that could be considered to improve the overall thermal comfort.
 Glazing to thermal mass ratio
 Depending on how much glazing is proposed, the amount of thermal mass should reflect
that ratio. The amount of thermal mass depends on if the sun is hitting the floor and walls
directly or indirectly ("Passive Solar Homes Glass-To-Thermal-Mass Ratios | Solar365", 2016).
YourHome.gov presents a visual chart for quickly determining this ratio depending on
location. See Appendix D.
 Materials
 The various interior surfaces inside the home can also have an effect on the retention of
heat. Some materials to consider for improved thermal comfort include carpet, thermal mass
in the partitions, exposed thermal mass (no plasterboard), curtains, and more.
 Humidity
 Although humidity was not a factor in this particular design assessment, in order to produce
the best design, it is essential that humidity is considered, particularly in a coastal location
like Sydney. One way to assess design strategies for particular climates is by using the
psychrometric chart. See Appendix E.
 Internal vents
 Internal vents increase the airflow from zone to zone, allowing heat to transfer internally
 Customized shading
 Shading should be customized to follow the sun path during each season. Appendix F
demonstrates this calculation. By customizing the shading, the heating loads can be
optimized for each season.
 Infiltration
 Infiltration was not considered in this design, however it is a critical element in optimizing
thermal design. There are elements of a building that are prone to air leakages, therefore
infiltration should be modeled so that appropriate bridging can be added. Appendix G
demonstrates the typical areas that air leakage occurs.
Further Changes to Consider

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Sydney Basin - climate | NSW Environment & Heritage. (2016). Environment.nsw.gov.au. Retrieved 24
May 2016, from http://www.environment.nsw.gov.au/bioregions/SydneyBasin-Climate.htm
Thermal mass | YourHome. (2016). Yourhome.gov.au. Retrieved 24 May 2016, from
http://www.yourhome.gov.au/passive-design/thermal-mass
Thomas, P. & Candido, C. (2016). Building Energy Analysis Assignment 2. Presentation, University of
Sydney.

Appendix A
Chart for Window Operation
Month Average High Average Low Prevailing Wind Window Position
Jan 27 21 E O
Feb 26 21 E O
Mar 25 18 NE/W O
April 23 15 E, S O:Day C:Night
May 19 13 W, S C
June 18 12 W, E C
July 17 9 W C
Aug 18 9 W C
Sep 21 12 W, E O:Day C:Night
Oct 23 15 W, E, S O:Day C:Night
Nov 23 17 E O:Day C:Night
Dec 24 8 E, W C
Uncomfortably Cold Hours vs Uncomfortably Hot Hours Zone 2
Appendix B

Appendix C
Chart for Window Operation Zone 1 Chart for Window Operation Zone 2
Month # of
Uncomfortably
Cold Hours
# of
Uncomfortabl
y Warm Hours
Window
Position
Jan 58 116 O
Feb 6.5 115 O
Mar 77 98 O
April 280.5 40 C
May 574.5 3.5 C
June 719 0 C
July 713 0 C
Aug 654 5 C
Sep 587 4.5 C
Oct 404.5 83.5 O: 12 - 16:00
Nov 156 69.5 O:Day C:Night
Dec 55 102 C
Month # of
Uncomfortably
Cold Hours
# of
Uncomfortabl
y Warm Hours
Window
Position
Jan 14 191.5 O
Feb 1.5 239.5 O
Mar 8 174.5 O
April 2.5 171 O: 10 – 22:00
May 442 15 C
June 647.5 0 C
July 677 0 C
Aug 603.5 6 C
Sep 326 6.5 C
Oct 114.5 122 O:Day C:Night
Nov 1.5 155.5 O: 9- 22:00
Dec 68 136 C
Month # of
Uncomfortably
Cold Hours
# of
Uncomfortabl
y Warm Hours
Window
Position
Jan 64.5 121 O
Feb 7.5 155 O
Mar 74.5 107.5 O
April 64.5 144 O:Day C:Night
May 536 3.5 C
June 713 0 C
July 713 0 C
Aug 651.5 4 C
Sep 419 14.5 C
Oct 195 136 O:Day C:Night
Nov 33.5 185 O:Day C:Night
Dec 167 93.5 C
Chart for Window Operation Zone 3
Appendix D
Thermal Mass – “Glass to Mass Ratios in Australian Cities”
("Thermal mass | YourHome", 2016)

Appendix F
“Rule of Thumb for Calculating the Width of Eaves”
("Passive solar heating | YourHome", 2016)
Appendix E
Psychrometric Chart – Sydney, Australia
(Climate Consultant, 2016)
Appendix G
Air leakage diagram
("Sealing your home | YourHome", 2016)

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